What’s the Best Way to Insulate the Floors Above My Crawlspace?

In the climate of the St. Louis area, homeowners with crawl spaces often have cold floors and high heating bills.  This is because their vented crawl spaces are filled with cold winter air.  The cold air directly under the house makes the floors cold and causes the furnace to run much more than it should. 

Fiberglass Batts Are Not the Solution

Homeowners in this situation often think of putting insulation under the floor.  So they go into the crawl space under the house and attach fiberglass rolls to the bottom side of the floor.  They have the right idea but end up without the warmer floors and lower heating bills they are looking for.

What went wrong?  The problem is, no matter how meticulously the fiberglass rolls are installed, they don’t keep the cold winter air from coming in contact with the floor above.  Air flows though fiberglass.  Rather than stopping the flow of cold air, fiberglass just filters the air as it passes through to the underside of the floor.

Making matters worse, over time gravity causes the fiberglass rolls to sag away from the floor.  Cold winter air then fills the gap between insulation and the floor.  At that point, the insulation might as well not be there.

Forget the Floors: Fix the Crawl Space!

The most effective way to warm up those cold winter floors and to lower the heating bills is to forget about the floor and worry about the crawl space.  Seal up the crawl space vents, access doors, rim joist, and any other penetrations to the outside in order to keep cold winter air from entering the crawl space.  Install a vapor barrier and insulate the floor and walls of the crawl space.

Once the crawl space is encapsulated, the air inside the crawl space will be warmed by heat lost from the house.  This heat will no longer be lost to the outside, instead it will be kept inside the crawlspace.  This, in turn, will warm the floors of the room above the crawl space, lessen the load on the furnace, and reduce the heating bill for the home.

It turns out, the best way to insulate the floors above your crawl space is not to insulate them at all. 

Contact us today to schedule your free estimate for crawl space encapsulation to achieve a more comfortable and energy efficient home!